Transmission line coupling and combining network for high frequency antenna array

ABSTRACT

An improved transmission line network includes signal coupling and combining sub-networks for interchange of high frequency energy between elements of a planar lineal antenna array and a monopulse radar transmitter and receiver having sum and difference channels.

United States Patent 1191 Rothenberg [451 July 16, 1974 TRANSMISSION LINE COUPLING AND [56] References Cited COMBINING NETWORK FOR HIGH UNITED STATES PATENTS FREQUENCY ANTENNA ARRAY 3,258,774 6/1966 Kinsey 343/854 [75] Inventor: Carl Rothenberg, North Bellmore, 3,345,585 lde u 3 3,509,577 4/1970 Kinsey 343/854 [73] Assignee: Isqperiz'yhlxlznd Corporation, Great Primary Examiner paul Gensler ec Attorney, Agent, or Firm-Howard P. Terry [22] Filed:. Apr. 19, 1973 21 Appl'. No.: 352,790 [57] ABSTRACT 3 An improved transmission line network includes signal coupling and combining sub-networks for interchange [52] 3 333/1 of high frequency energy between elements of a planar lineal antenna array and a monopulse radar trans- [51] Int. Cl G015 9/02, HOlp 5/00 [58] Field Of Search 333/6, 10, 11; 343/16 M, 22,? and rewver havmg Sum and fj'fference Chan r 6 Claims, 9 Drawing Figures I 1 :1. 2 .00 Q1 -2 L'73%+1 %+2 009 N 1 llllllll llllllll 26 27- 25 j {280 {27a [26a [25a TRCVR TRCVR TRCVR TRCVR TRCVR TRCVR TRCVR TRCVR m 4- "\.-93 43 44 N57 45 88 46 x59 57 91 92 5.... e e n u M d 4 4 i" 1 ii- 1 w w 61 16 r r r 6 39 [21 I22 231 f 250 -22a 21a 20a 47 4a 49 5O 4 50a 370 \& \k,,\\ d J J J l J :2 w L37 X x 62 X r 490 r 480 470 r 4011 51 52 53 54 59 54 a 53 a 52 0 510 \k e 5 J/ J/,, J/ V' L f f. l r V 'v' 41 N 388 N l W 65 38 0 410 5&6 35, :5 3 g 30 I; 31 I; 32 f; 9-330 320 3 -30a /5- 15 3 r 64 I 11 l A 9S9 12 l CHANNEL RECEIVER 1 97 55 TRANSMITTER CHANNEL x14 L98 sum '1 or 4 I PAIENTED JUL 1 61974 AIENTIEUJUUSISH 3.824.500

SHEET 2 0F 4 F I G 2.

73 Z RECEIVE 2 A RECEIVE f TRANSMIT Z RECEIVE f2 TIRANSMIT SCANNING PHASE SH l FTER AREcElvE PRE- PLI FIER DUPLEXER POWER 1 AM PLI FIER' TRANSMISSION LINE COUPLING AND COMBINING NETWORK FOR HIGH FREQUENCY ANTENNA ARRAY BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates generally to transmission and reception multiple-element antenna arrays and distribution circuits for use with them and more particularly to such antenna arrays and networks having multiple modes of operation adapted for use'in monopulse radar apparatus.

2. Description of the Prior Art Prior art lineal or planar antenna arrays have been developed with some degree of success for operation in monopulse radar systems. However, such prior art systems generally have one or more of several difficulties. The networks used with the arrays for distributing energy to the elements of the antenna array and for combining received signals have often been complex. They therefore have proven difficult to manufacture in compact form and cost, weight,'and size have often been excessive. Generally, the network concepts employed in the prior art have been lossy and have also not permitted independent and compatible control over the transmitter radiation pattern and the effective monopulse sum and difference receptivity patterns. It has been necessary even to use separate antennas for performing the transmission and reception functions in certain circumstances.

SUMMARY OF THE INVENTION The present invention provides a planar antenna array and associated transmission line networks including a signal combining transmission line network and a pair of signal coupling transmission line networks coupling the signal combining network to the individual elements of the antenna array. The combining and coupling functions are performed in a manner such that a single array may be used in several modes. The networks simultaneously provide independent control over the transmitter radiation pattern and the monopulse sum and difference receptivity patterns in a single antenna aperture. At the same time, the novel array antenna and network configurations permit antenna pattern scanning by conventional means.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram of one embodiment of the invention illustrating its connections to a typical antenna array and to monopulse radar transmitter and receiver apparatus.

FIGS. 2 and 3 are graphs useful in explaining operation of the apparatus of FIG. 1.

F IG. 4 illustrates an alternative of the arrangement of FIG. 1.

FIGS. 5 and 6 are respective plan and cross section views of an embodiment of FIG. 1 employing a strip transmission line network.

FIGS. 7 and 8 are respectively plan and cross section views of an embodiment of FIG. 4 employing a strip transmission line network.

FIG. 9 is a circuit diagram of a phase shift circuit which may be used with the embodiments of FIGS. 1 0r 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention, as seen in general form in FIG. 1, is an improved high frequency, substantially lossless transmission line network 9 for interchange of high frequency energy between an array 10 of spaced antenna elements 1 through N and a monopulse radar transmitter 11 or monopulse radar receiver 12. Receiver 12 includes a conventional monopulse signal difference channel 13 and a conventional monopulse signal summation channel 14. The function of the novel network 9 is to provide a substantially uniformly illuminating radiation pattern in the plane of array 10 in the transmission mode of operation of the radar system and also to provide a desirable and independent tapered receptivity pattern in the plane of array 10 when the system operates in its monopulse reception mode. In the receiving mode, the novel network 9 effectively provides a tapered, high gain, low side lobe, summation receptivity pattern. At the same time, it effectively provides a high angular-sensitivity, low side-lobe, difference receptivity pattern. The network 9 has other attributes desirable in radar antenna array systems, including minimum loss, volume, weight, and cost, and is capable of transmitting relatively high frequency signals of relatively high power level, as will be described. As will be seen, the network 9 may be constructed as a planar system for feeding antenna elements also lying in the same plane. In this manner, successive layers may be formed of such configurations one on top of the other for providing volume scanning.

The novel transmission line network 9 consists of three major portions. The central signal combining transmission line network 16 combines signals flowing between the radar transmitter 11 and receiver 12 and the two remaining parts of network 9. These remaining parts of network 9 are symmetrically disposed in the same plane about combining network 16 and comprise signal coupling transmission line networks 15 and 15a, the coupling sub-networks l5 and 15a being essentially mirror image configurations of each other. Signal coupling networks 15, 15a serve to permit high frequency energy interchange between signal combining network 16 and array 10. In many applications, array 10 will consist of equally spaced antenna elements I through N (the greater spacing between antenna elements M2 and M2 1 has been introduced in FIG. 1 simply as a matter of convenience in making the drawing clear).

Signal coupling transmission network 15 consists in part of an array of substantially parallel transmission lines, such as transmission lines 20, 21 and 22, 23. Each such transmission line is coupled through a transceiver element such as transceiver elements 25, 26 and 27, 28 to one of the antenna elements of array 10. For example, transmission line 20 is coupled through transceiver 25 to antenna element 1, while transmission line 21 is coupled through transceiver 26 to array element 2. Each of the transmission lines 20, 21 and 22, 23 is coupled at its end opposite array 10 to a respective one of the matched high frequency energy absorbing terminations 30, 31 and 32, 33.

In energy coupling relation with transmission lines 20, 21 and 22, 23 and in generally orthogonal relation therewith is a second set of substantially equally spaced transmission lines 36, 37, and 38 connected at their inner ends to combining network 16. At the ends of transmission lines 36, 37, 38 opposite combining network 16, the respective transmission lines are terminated by matched energy absorbing loads 39, 40, and 41, which may be generally similar to the matched energy absorbing loads 30, 31 and 32, 33. Transmission lines 36, 37, 38 form a generally regular grid in cooperation with transmission lines 20, 21 and 22, 23 and at each of the intersections of the orthogonally disposed transmission lines is placed an energy coupling device such as a directional coupler; such couplers are represerited at transmission line intersections 43 through 54 in coupling network 15. The degree of coupling of each such coupler is adjusted in a predetermined manner, as will be described.

Coupling network 15a is similar to coupling network 15 and consists in part of an array of substantially parallel transmission lines, such as transmission lines 20a, 21a and 22a, 23a. Each such transmission line is again coupled through a transceiver element such as transceiver elements 25a, 26a and 27a, 28a to one of the antenna elements of array 10. For example, transmission line 20a is coupled through transceiver 25a to antenna element N, while transmission line 21a is coupled through transceiver 26a to array element N- 1. Each of transmission lines 20a, 21a and 22a, 23a is coupled at its end opposite array to a respective one of the matched high frequency energy absorbing terminations 30a, 31a and 32a, 33a.

In energy coupling relation with transmission lines 20a, 21a and 22a, 23a and in generally orthogonal relation therewith is again a second set of substantially equally spaced transmission lines 36a, 37a, and 38a connected at their inner ends combining network 16. At the ends of transmission lines 360, 37a, 38a opposite combining network 16, the respective transmission lines are terminated by matched absorbing loads 39a, 40a, and 41a. Transmission lines 360, 37a, 38a again form a generally regular grid in cooperation with transmission lines 20a, 21a, and 22a, 23a and at each of the intersections of the orthogonally disposed transmission lines is placed a hybrid or coupling device such as a directional coupler; such couplers are represented at transmission line intersections 43a through 54a in signal coupling transmission line network a. The degree of coupling of each such coupler is again adjusted in a predetermined manner.

As noted in the foregoing, the mirror image energy or signal coupling networks 15 and 15a are coupled in energy exchanging relation with the centrally disposed signal combining transmission line network 16. This connection is made by the oppositely arrayed transmission line sets 36, 37, 38 and 36a, 37a, 38a. Transmission lines 36 and 360 are coupled to a conventional four-port hybrid circuit 57, lines 37 and 37a to four-port hybrid circuit 58, and lines 38 and 38a to four-port hybrid circuit 59. The sum port of hybrid circuit 57 is connected to transmitter 11. The sum port of hybrid circuit 58 is connected to the sum channel 14 of receiver 12. The sum port of hybrid circuit 59 is coupled directly to the matched terminating load 60. The difference port of hybrid circuit 57 is coupled through a fixed phase shifter 61 and a first side of directional coupler 62 to the matched terminating energy absorbing load 63. The difference port of hybrid circuit 58 is coupled through a second side of directional coupler 62 and a first side of directional coupler 64 to the difference channel 13 of receiver 12. The difference port shifter 65 and the second side of directional coupler 64 to the matched terminating load 66. Phase shifters 61, 65 may each be 180 phase shifters of known type. In general, or 270 phase shifters may be employed depending upon the phase characteristics of the selected directional couplers and hybrid circuits.-

The novel network 9 provides three independent signal distributions in connection with array 10; namely, a sum distribution during signal transmission, an independent sum distribution during reception, and an independent differential distribution during reception. In the sum transmission mode, the configuration is designed to place equal voltages at the inputs of each of the transceivers 25, 26, 27, 28 and 25a, 26a, 27a, 28a. The voltage levels are such that each of the power amplifiers in the transceivers operate near saturation, so that their outputs are equal and so that maximum power is radiated from array 10. The summation channel 14 of receiver 12 is operated with an array receptivity pattern having an even tapered voltage distribution with low side lobes and high aperture directivity. The differential channel 13 of receiver 12 is operated with an array receptivity pattern having an odd tapered voltage distribution with low pattern side lobes and high angular sensitivity. In the novel transmission line network 9, the three special requirements are achieved through the nature of the two signal coupling transmission line networks 15, 15a and the cooperating signal combining transmission line network 16.

In the generalized design procedure for the network 9, the procedure is to select the number of array ports 86 through 93 where transmission lines such as transmission line 20 are to be coupled through transceivers such as transceiver 25 to successive antenna array elements like array element 1, and then to determine what types of space signal patterns or illumination functions are required for each of channels 11, 13, and 14. It has been shown that the orthogonality relationship,

for a lossless network, can be expressed as:

I l for j V,--V 2 J 0forjlt (1) where V is the complex voltage at the ith port of the ports 86 through 93 when coupled to transceivers 25 et al., for unit power level at port j of ports 97, 98, and 99.

where* indicates the complex conjugate in the usual manner. Since the port 99'sum transmit'voltage vector V in FIG. 2 is even,

N l I E VHVf 0 i=l In order to satisfy the requirement that:

the sum transmit vector is selected as in FIG. 2 so that:

Equation (5) places a restriction onthe sum transmit voltage vector V,- at'port 99 to achieve the network or- I an even functionof displacement from the bore sight axis 73. The network 9 is substantially lossless, having a 180? phase increment in the sum transmit channel as compared to the sum receiver channel, necessitating correction by controlled insertion of a 180 phase shifter in certain of the transceiver modules 25, 26, 27, 28, 25a, 26a, 27a, 28a. The 180 phase is applied to those transceiver modules so that the 180 phase step for the transmit channel of FIG. 2 results in an equal phase transmit signal at the antenna elements 10 of FIG. 1.

As seen in FIG. 1,"the sum transmit port 99 from transmitter 11 is connected directly only to transmission line 36, 36a of the network 9. The sum receiver port 98 from receiver portion 14 is connected directly onlyto transmission line 37, 37a of network 9, while the differential receiver port 97 is connected from receiver portion 13 to all three of the transmission line pairs 36, 36a, 37, 37a, and 38, 38a. Alternate designs may readily be generated by those skilled in the art, using various combinations of the series lines 36, 37, 38, 36a, 37a, 38a, and various arrangements for the combining network 16 to generate the sum transmit channel 11, the sum receive channel 14, and the difference channel 13. For example, an alternate arrangementmay usethe odd function summation transmit voltage vector 75 as shown in FIG. 3 with the odd differential receive function 76and the even summation receive function 77 of FIG. 3.

FIG. 4 illustrates one specific form which the invention may take where a lineal planar antenna array 10 having eight antenna elements 1 through 8 is desired. Corresponding reference numerals are used in FIGS. 1 and 4 for corresponding parts, including receivers 25,

26, 27, 28, a, 26a, 27a, and 28a, first sets of transmissite directions from hybrid circuit 57 and have regularly spaced directional couplers 44, 45, 46, 44a, 45a, and 46a respectively coupling to the orthogonal set of transmission lines including lines 21, 22, 23, 21a, 22a, and 23a. An end of transmission line 36 opposite hybrid circuit 57 is connected directly by a conductor at location 67 to transmission line 20; correspondingly, an end of transmission line 36a opposite hybrid circuit 57 is connected directly to transmission line 20a by a conductor at location 67a.

Transmission lines 37, 37a extend in opposite directions from hybrid circuit 58 and have regularly spaced directional couplers 49, 50, 49a, 50a respectively coupling to the set of orthogonal transmission lines including transmission lines 22, 23, 22a, and 23a. An end of transmission line 37 opposite hybrid 58 is connected by a conductor at location 68 directly to transmission line 21; correspondingly, an end of transmission line 37a opposite hybrid 58 is connected directly by a conductor at location 68a to transmission line 21a.

Transmission lines 38, 38a extend in opposite directions from hybrid circuit 59 and are coupled respectively through directional couplers 54 and 54a to orthogonal transmission lines 23 and 23a. An end of transmission line 38 opposite hybrid 59 is connected directly by a conductor at location 69 to transmission line 22; again, and in corresponding manner, an end of transmission line 38a opposite hybrid 59 is connected directly by conductor at 69a to transmission line 27a.

Hybrid junctions 57, 58, and 59 are again essential elements of the central signal combining network 16, cooperating as before with mirror image coupling networks 15, 15a. For this purpose, the difference channel of hybrid circuit 57 is connected directly to the diffen ence channel13 of monopulse receiver 12. The sum port of hybrid circuit 57 is coupled through a first side of directional coupler 80 to the summation channel 14 of receiver 12. The difference port of hybrid circuit 58 is coupled through a second side of directional coupler 80 to a matched terminating load 81. The sum port of hybrid circuit 58 is fed with power by transmitter 11. The respective sum and difference arms of hybrid circuit 59 couple to the respective matched terminating loads 82 and 83. Directional coupler 84 has a first side coupled between hybrid circuit 59 and load82 and a second side coupled between transmitter 11 and hybrid circuit 58.

In the arrangement of FIG. 4, the difference receiver channel 13 directly uses only. the transmission line 36, 36a of network 9. The summation receiver channel 14 directly uses the transmission lines 36, 36a and 37, 37a, while the summation transmitting channel directly uses transmission lines 37, 37a and 38, 38a.

If an array antenna having the characteristics shown in FIG. 3 is desired, the voltage contributions of the individual ports 86 through 93 of network 9 connected to array elements 1 through 8 from the transmitter 11, receiver sum channel 14, and difference channel 13 Y may be selected according to the foregoing theory. As

an example, the contributions at the array ports 86 through 93 may be selected as follows:

Channel 11, 13, and 14 Voltages -Continued Channel 11, 13, and 14 Voltages Port i Transmit Sum Receive Delta Receive Port 99 Port 98 Port 97 92 l/\/8 0.267 -l/V 6 93 1/\/8 0.157 I l/Vl2 Coupler Voltage Ratio 44, 44a 0.8 l650 45, 45a 0.63246 46, 46a 0.40825 49, 49a 0.97769 v 50, 50a 0.89030 54, 54a 0.99339 Hybrid circuits 57, 58, and 59 are preferably 3 dB. hybrid circuits of the magic-tee type, though other kinds of hybrids may be used.

As noted in the foregoing, a significant feature of the present invention lies in the fact that it may be constructed in the form of a thin planar layer; for this purpose, the transmission lines employed are preferably of the strip or planar transmission line type as shown in FIGS. 5 through 8.

FIGS. 5 and 6 represent one general way in which the coupling network of FIG. 1 may be constructed of a strip transmission line set 36, 37, 38 and of an orthogonal set of transmission lines 20, 21, 22. The sets may be formed on the low loss dielectric sheet 100 (FIG. 6) by bonding each side of the sheet in a conventional manner with a thin layer of a conductive metal, such as copper.The desired circuit patterns are established in the copper sheets by use of a photoresist or other mask, after which undesired metal is etched away. After removal of the mask, the desired circuits remain on each side of sheet 100.

In the view seen in FIG. 5, it will be understood that, for the sake of clarity in the illustration, the dielectric sheet 102 is seen with three substantially parallel transmission lines 36, 37, 38 as if they were resting on the upper surface of dielectric sheet 102. Dielectric sheets 100 and 101 are not shown in FIG. 5, but the orthogonal array of transmission lines 20, 21, 22 is shown simply as if suspended in space above transmission lines 36, 37, 38. The strip transmission line 86 extends from port 86 through over lay couplers 43, 47, and 51 to termination 30. Couplers 44, 48, 52 and 46, 50, 54 are similarly disposed in the orthogonal transmission lines 21 and 22.

Ports 86, 87, 88 will be arranged for direct connection to respective ports of transceivers such as transceiver 25. The over-lay directional couplers are of conventional type having, as in coupler 51, a section of the transmission line overlying transmission line 38 for a distance of M4, where A is the operating wave length. The off-set distance D, as in coupler 48, determines the Coupling ratio between transmission lines 21 and 37, for example. The matched energy absorbing terminations 30, 31, 32 associated with couplers 51, 52, 53 may be of the kind disclosed in the Denhard U.S. Pat. No. 3,585,533 for Microwave Microcircuit Element with Resistive I-IighFrequency Energy Absorber, issued June 15, 1971 and assigned to the Sperry Rand Corp. FIG. 6 illustrates the compact nature of the network 15 wherein the inner dielectric sheet with circuits on each of its sides is sandwiched between dielectric cover sheets 101, 102. The transmission lines 36, 37, 38 are seen in cross section on one side of dielectric sheet 100, while a portion of the orthogonal transmission line 21 is seen on the opposite side of dielectric sheet 100.'

FIGS. 7 and 8 illustrate in the same general manner a construction suitable for the signal coupling network transmission line 15 of FIG. 4. Again, FIG. 7 shows the same type of structure as FIG. 8 with dielectric sheets 100 and 101 not shown, so that transmission lines 21, 22, 23 seem simply to be suspended in air above dielec tric sheet 102. In this instance, transmission lines 36, 37, 38 need not be provided with matching energy absorbing terminations, but may be conductively joined by pins at locations 67, 68, 69. The conductive pin 68 is seen in the figures projecting through dielectric sheet 100 to join transmission line 37 to portion 106 of transmission line 21. It will be appreciated that thicknesses in FIGS. 6 and 8 are grossly exaggerated for purposes of clarity in the illustration and that layers 100, 101, 102 may actually have thicknesses of about three tenths of a centimeter, for example. Further to illustrate the size of the structure, transmission lines 20 and 36 may have widths of about two thirds of a centimeter.

The transceivers 25, 26, 27, 28, 25a, 26a, 27a, 28a in themselves do not necessarily form a particular part of the present invention, since there is a wide variety of such arrangements known in the prior art. However, one suitable transceiver, to be discussed in connection with the representative transceiver 25, is illustrated in FIG. 9. Signals to be transmitted are injected into transceiver 25 at port 86 and pass through the scanning digital phase shifter 110, which device may, for example, be a conventional high-frequency four-bit, digital diode phase shifter of known type whose phase changing characteristic is controlled in the usual manner by digital control signals applied to one or more of phase shifting inputs 111, 112, 113, 114, 115. The output of the scanning phase shifter 110 is then amplified by power amplifier 116 and is thus controlled in a conventional As noted with reference to FIG. 1, it is necessary to compensate for the nature of network 9 by controllably inserting a compensating phase shift for some of the transceiver modules. This may be accomplished in an ordinary manner by adjusting the digital control signal applied to the scanning phase shifter 110. The scanning phase shifter 110 thus provides 180 phase compensation between the transmit and receive modes without the need of additional equipment.

While the invention has been described in its preferred embodiments, it is to be understood that the words which have been used are words of description rather than of limitation and that changes within the purview of the appended claims may be made without departure from the true scope and spirit of the invention in its broader aspects.

I claim:

1. Transmission line means comprising: 7

signal combiner transmission line network means including first, second, and third hybrid circuit means each having first, second, third, and fourth port means, i

said first port means of said first hybrid circuit means being coupled with transmitter means,

said first port means of said second hybrid circuit means being coupled with the sum channel of re ceiver means, I I

said second port means of said second hybrid circuit means being coupled with the difference channel of said receiver means,

said first and second port means of said third hybrid circuit means being coupled with respective matched terminating energy absorber means,

said second port means of said first hybrid circuit means being coupled with said second port means of said second hybrid circuit means,

said second port means of said third hybrid circuit means being coupled additionally with the difference channel of said receiver means, and

first and second coupling transmission line network means each having first and second pluralities of signal coupling ports,

said first plurality of signal coupling ports of said first coupling transmission line network means being coupled in energy exchanging relation with said third port means of said hybrid circuit means,

said first plurality of signal coupling ports of said second coupling transmission line network means being coupled in energy exchanging relation with said fourth port means of said hybrid circuit means, and

said second plurality of signal coupling ports being coupled with discrete antenna elements of a lineal antenna array.

2. Apparatus as described in claim 1 wherein said 1 first and second signal combining transmission line network means comprise:

first and second pluralities of individual transmission lines respectively coupled in first coplanar relation with said third and fourth port means of said hybrid junction means,

a third plurality of mutually spaced transmission lines substantially orthogonally disposed with reference to said first plurality of transmission lines in second coplanar relation therewith, and

plural over-lay signal coupler means for permitting energy exchange between eachindividual of said first and second pluralities of transmission lines.

3. Apparatus as described in claim 2 including 10 matched terminating energy absorber means coupled at one end of each. of said first and second pluralities of transmission lines.

4. Transmission line means comprising: signal combiner transmission line network means including first, second, and third hybrid circuit means each having first, second, third and fourth port means, said first port means of said first hybrid circuit means being coupled with the sum channel of receiver means, said second port means of said first hybrid circuit means being coupled with the difference channel of said receiver means, said first port means of said second hybrid circuit means being coupled with transmitter means, said first port means of said first hybrid circuit means being coupled additionally with said second port means of said second hybrid circuit means, said respective first and second port means of said third hybrid circuit means being coupled with matched terminating energy absorber means, said first port means of said second hybrid circuit means being additionally coupled with said second port means of said third hybrid circuit means, and first and second signal coupling transmission line network means each having respective first and second pluralities of signal coupling ports, said first plurality of signal coupling ports of said first coupling transmission line network means being coupled in energy exchanging relation with said third port means of said hybrid circuit means, said first plurality of signal coupling ports of said second coupling transmission line network means being coupled in energy exchanging relation with said fourth port means of said hybrid circuit means, and said second plurality of signal coupling ports being coupled with discrete antenna elements of a lineal antenna array. 5. Apparatus as described in claim 4 wherein said first signal coupling network comprises:

first, second, and third transmission lines respectively coupled with said third port means of said hybrid circuitmeans in coplanar relation, fourth, fifth, sixth, and seventh mutually spaced transmission lines substantially orthogonally disposed in second coplanar relation with respect to said first coplanar plurality of transmission lines in energy coupling relationship therewith, said first transmission line being coupled with said fourth, fifth, sixth, and seventh transmission lines, said second transmission line being coupled with said fifth, sixth, and seventh transmission line, and said third transmission line being coupled with said sixth and seventh transmission lines. 6. Apparatus as described in claim 5 including matched terminating energy absorber means coupled only at one end of said seventh transmission line. 

1. Transmission line means comprising: signal combiner transmission line network means including first, second, and third hybrid circuit means each having first, second, third, and fourth port means, said first port means of said first hybrid circuit means being coupled with transmitter means, said first port means of said second hybrid circuit means being coupled with the sum channel of receiver means, said second port meaNs of said second hybrid circuit means being coupled with the difference channel of said receiver means, said first and second port means of said third hybrid circuit means being coupled with respective matched terminating energy absorber means, said second port means of said first hybrid circuit means being coupled with said second port means of said second hybrid circuit means, said second port means of said third hybrid circuit means being coupled additionally with the difference channel of said receiver means, and first and second coupling transmission line network means each having first and second pluralities of signal coupling ports, said first plurality of signal coupling ports of said first coupling transmission line network means being coupled in energy exchanging relation with said third port means of said hybrid circuit means, said first plurality of signal coupling ports of said second coupling transmission line network means being coupled in energy exchanging relation with said fourth port means of said hybrid circuit means, and said second plurality of signal coupling ports being coupled with discrete antenna elements of a lineal antenna array.
 2. Apparatus as described in claim 1 wherein said first and second signal combining transmission line network means comprise: first and second pluralities of individual transmission lines respectively coupled in first coplanar relation with said third and fourth port means of said hybrid junction means, a third plurality of mutually spaced transmission lines substantially orthogonally disposed with reference to said first plurality of transmission lines in second coplanar relation therewith, and plural over-lay signal coupler means for permitting energy exchange between each individual of said first and second pluralities of transmission lines.
 3. Apparatus as described in claim 2 including matched terminating energy absorber means coupled at one end of each of said first and second pluralities of transmission lines.
 4. Transmission line means comprising: signal combiner transmission line network means including first, second, and third hybrid circuit means each having first, second, third and fourth port means, said first port means of said first hybrid circuit means being coupled with the sum channel of receiver means, said second port means of said first hybrid circuit means being coupled with the difference channel of said receiver means, said first port means of said second hybrid circuit means being coupled with transmitter means, said first port means of said first hybrid circuit means being coupled additionally with said second port means of said second hybrid circuit means, said respective first and second port means of said third hybrid circuit means being coupled with matched terminating energy absorber means, said first port means of said second hybrid circuit means being additionally coupled with said second port means of said third hybrid circuit means, and first and second signal coupling transmission line network means each having respective first and second pluralities of signal coupling ports, said first plurality of signal coupling ports of said first coupling transmission line network means being coupled in energy exchanging relation with said third port means of said hybrid circuit means, said first plurality of signal coupling ports of said second coupling transmission line network means being coupled in energy exchanging relation with said fourth port means of said hybrid circuit means, and said second plurality of signal coupling ports being coupled with discrete antenna elements of a lineal antenna array.
 5. Apparatus as described in claim 4 wherein said first signal coupling network comprises: first, second, and third transmission lines respectively coupled with said third port means of said hybrid circuit means in coplanar relation, fourth, fifth, sixth, and sEventh mutually spaced transmission lines substantially orthogonally disposed in second coplanar relation with respect to said first coplanar plurality of transmission lines in energy coupling relationship therewith, said first transmission line being coupled with said fourth, fifth, sixth, and seventh transmission lines, said second transmission line being coupled with said fifth, sixth, and seventh transmission line, and said third transmission line being coupled with said sixth and seventh transmission lines.
 6. Apparatus as described in claim 5 including matched terminating energy absorber means coupled only at one end of said seventh transmission line. 